Abstract:
This study aims at investigating both lexical and tonal variation by two social variables-age-group and ease of communication. The Thai variety selected for this study is Khorat Thai due to its unique status as a hybrid variety between Central Thai and Northeastern Thai. The informants were selected on the basis of the following two criteria: age-group (15-20, 40-45, and over 60 years old) and place of residence (one with easy access i.e. Tambon Ma Kha, and the other with difficult access i.e. Tambon Ban Lang, both of which are in Non Thai district, Nakhon Ratchasima or Khorat province. Ten informants per age-group per location were selected. In all sixty informants were interviewed. The questionnaire designed to elicit lexical variation consists of 50 semantic units. Each is represented by different lexical items in Khorat Thai, Bangkok Thai, and Northeastern Thai. The questionnaire for eliciting tonal variation consists of 10 tokens of each of the 12 live-syllable words and 4 long checked-syllable words. The selected words are distinguished by tone either in identical or analogous environment. Five tokens of each words which have the best recording quality were acoustically analyzed using the PRAAT software. This study finds that Bangkok Thai lexical items occur most frequently followed by Thai Khorat lexical items. Northeastern Thai lexical items occur least frequently. The data were analyzed statistically setting the 0.01 confidence level as the criterion. It was found that in the overall picture age-group is the main variable influencing variation in lexical usage. However, when comparing two age-groups at a time, the only pair differs is the 15-20 and the over 60 age-groups. When the ease of communication varible is controlled, it is found that in the tambon with easy access age-group is related to lexical usage whereas in the tambon with difficult access it is not. Thus, it may be concluded that age-groups is not regularly to variation i Khorat Thai. Regarding relationship between ease of communication and lexical usage it is found that in the overall picture they are not related. When controlling age-group it is found that the 15-20 age-group in the two types of tambon differ in their lexical usage. It is possible to conclude that variation in lexical usage is found only in the young age-group in tambon with easy access. The other age-groups do not differ in their lexical usage either in the tambon with easy access or difficult access. Tone is found not to vary either by age-group or ease communication. All of the informants still use the Khorat four tone sysyem-low rising, mid gliding down, low falling, and high falling. The phonetic characteristics of all of the tones are also the same. Using the tone box method it is found that the two tambons differ in the split in column A, Tambon Ma Kha uses the A123-4 pattern while Tambon Ban Lang uses the A1-234 pattern. The tone split and merge pattern of tambon Ban lang has been found in the previous study whereas those of tambon Ma Kha had not occurred in the previous study. This study finds that lexical change occurs faster than tonal change. At present the Khorat Thai speakers increasingly use Bangkok Thai lexical items but they still use the Khorat Thai tone system.